So I have a bunch of older PC's and parts laying around the house collecting dust and started thinking to myself it might be cool to put them to use and make a dedicated HTPC. I've looked through a couple "guides" there's a couple questions that come to mind.

Why would anyone bother building a HTPC when the guides are recommending builds that vary anywhere between 1000 and 1500 bucks worth of parts. That's insane!

What's the point of a TV tuner card? Often times in the suggested builds the most expensive part seems to always be the tuner card usually at anywhere between 300 and 400 bucks. From my understanding this card allows the PC to receive a TV signal so that I can watch my, for example, bell satellite tv and also record anything I watch. Not really seeing the point of blowing that much cash when years back my dad got the tivo version of the satellite box that has 50 hours worth of space and if I remember correctly it only cost 100 dollars over the free non tivo default model.

And lastly I'm wondering if on board graphics are enough to watch 1080p on an older model CPU (honestly have no clue which ones came in the dell pc's my dad bought a year ago), or would I need to buy a graphics card. We have a 37 " tv.

It would depend on what the on board graphics chipset is actually. I am using onboard for my own htpc, however it's chipset is an hd4200 which is performing all the work. Certain older onboard chipsets are just basic ones and dont contained a chopped down graphics processor such as mine.

I have been building HTPC's for myself & friends for a while and I have a few observations for you.

1) With respect to a minimum cpu requirement, I have an Intel E5200 (@3Ghz) in my personal build, the video chipset of your motherboard or discreet video card will be of most importance.

2) While HTPC's with "modern" graphics do not need a monster cpu, as most video processing will be done by the GPU, this doesn't mean that the cpu choice can be anything. While the Nvidia Ion & AMD Fusion ITX motherboard Gpu's may be great at video decoding & playback, they are paired with cpu's that on the definite low end with respect to general computing. Also to keep in mind is that there may be one or two videos you may encounter where the GPU may not play a part due for example to how the video was encoded in the first place. The cpu then will do all the grunt work. This happens less & less with modern gpu's but keep that in mind. Also to bear in mind is that one of the advantages of building an HTPC is that you can do more with it, if you want, than just enjoy media.

4) Total HTPC cost is not very much even for a machine that can play back the vast majority of video codecs in clear 1080p. The $1000-$1500 builds are overkill where sometimes the case is the most expensive part on those "Luxury" builds.

E2200 Allendale 2.2GHz, Dual Core CPU (LGA 775) with stock heatsink / fan
2x 1 gb no name ram sticks at 667 mhz
This setup is running on a no name mobo that has room for two more ram sticks and what seems to be a 16x PCI lane and two 8x lanes.
200 gb western digital hard drive.
No name 350W PSU.

In a really old gaming rig the only thing worth salvaging was the video card, it's a 5700 LE 256 MB nvidia card with a DVI connection.

If I popped the video card in the above mentioned rig would that be enough to stream 1080p on a 37" TV? I'm gonna try it anyways but i'm hopping so.

Before I decide to go ahead and buy some parts, if any are needed, I wanna test this out and see how well it works. For the time being seeing as storage capactiy would be an issue, I'm just gonna network the PC and use storage from my main computer.

Alright we got a problem team. The damn video card isn't fitting in the largest lane. Upon closer inspection the mobo is by foxconn and it's the G333M02 model. According to the spec's it's supposed to have 1 x PCIe x16, 1 x PCIe x1, 2 x PCI.

Pick up a cheap vid card. I have two HTPCs with ATI 4xxx graphics and they work perfectly. I don't know if there is any advantage with a higher card except that AFAIK 5xxx and up can also pass audio over the HDMI. Kingnubian has some links above. Just pay attention to the cooling solution as some cheap vid card coolers can be really noisy.